Yes, Queralt is a Catalan name for girls. Actually, it's a name of a marian sanctuary near Berga (a town in the Barcelona Province): Mare de Déu de Queralt (Our Lady of Queralt).
The toponyme of "Queralt" comes from the Catalan Quer ("large rock, crag" in Catalan toponymes) + alt ("high").
The name day is 8th
September.
http://www.ajberga.es/queralt/santuquer.htm (in Catalan)
Lumia